Appreciating classics: Prewar Bentley 'Bobtail' could fetch $7.5M

John McIlroy is Deputy Editor of Auto Express and Carbuyer. The views expressed here are solely his own.

More car manufacturers than ever are targeting the super-rich, developing even faster "hypercars" that cost well over a million dollars apiece, or offering bespoke tailoring and customization of vehicles that can rack up similar price tags.

Wealthy car fans can feed their habit with these high-performance technological marvels or customize their new vehicle to their own desires.

But hardcore collectors go beyond modern motoring and bid for the classics.

This weekend, the latest RM Sotheby's auction in Amelia Island, Florida, will showcase just how strong the market is for slices of automotive history.

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Having the latest supercar has its appeal, of course. But spending two, three, four or even five times the price of a Bugatti Chiron can get you more than just limited-edition appeal; it buys heritage, providence and soul.

One of the stars of the Amelia Island auction is a Bentley that illustrates this point perfectly.

It's a prewar, 4½ Liter racer, created by the British manufacturer's founder, W.O. Bentley, to give his drivers a better chance in the famous Le Mans 24 Hours endurance race.

The particular car is known as the "Bobtail" because of the rear bodywork Bentley crafted to help it slip through the air on the Le Mans circuit's long straights.

And while it retired with a cracked chassis frame on its first attempt at the race in 1928, it returned 12 months later to claim a podium finish as part of a Bentley 1-2-3-4.

The history of classic cars is a minefield, and can be particularly troublesome when it comes to prewar creations, doubly so if they were employed in the ruthless world of motorsport.

Indeed, Sotheby's own documentation on the car admits that while it is listed with both a chassis and engine number, it may have had an entire chassis frame change after its first Le Mans outing.

But enough is known about the rest of its life -- its ownership history and some of the famous "Bentley boys" racers who took the wheel -- for the car to command an estimated price between $6.5 million and $7.5 million when it comes under the hammer this weekend.

Nor, it must be said, is the 4½ Litre likely to be the most expensive vehicle at Amelia Island.

A pair of Ferraris -- a 1950 166 MM Barchetta by Touring, and a 1961250 GT SWB Berlinetta by Scaglietti -- are listed with estimates that are a couple of million dollars higher than the British prewar special.

Classic car revival

The classic car auction market has not always been this buoyant. In the 1970s you could pick up troublesome, unloved Italian sports cars relatively cheaply.

Even the rare Ferrari 250 GTO was a hard vehicle to shift; some changed hands for $10,000 or less.

These days, you'd be looking at a bill of at least $40 million for a GTO, assuming one of the 39 genuine examples was up for sale in the first place.

The GTO's appreciating value is at the extreme end of the market trend, but it is not unique.

This has made investment in classic automobiles the sort of cast-iron banker of an investment that attracts people who've made money by being able to spot, well, cast-iron bankers of investments.

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A vintage car -- particularly anything with a custom body by an illustrious coachbuilder of the era -- is something that can be enjoyed, on the move or stationary, while its rising value more than pays for its maintenance.

The top few percent of classic cars have moved beyond property, in fact, to be on a level with works of art.

Classic design

Even if you discount the history of the cars concerned, the fact remains that they are genuine, bona fide proof of how distinct, bold and creative car designers were able to be half a century or more ago.

These days, crash regulations, fuel efficiency, the laws of physics and the rulebook laid down by wind-tunnel testing mean that cars are looking more and more similar.

By contrast, designers up to the 1960s took function into account, but also focused on what looked good, resulting in creations like the achingly beautiful 250 GT SWB that will be sold in Florida.

Or in the case of the Bentley, they exploited the relative freedom of old-school motorsport regulations to make a handful of cars that are fast approaching their hundredth birthday.

The modern-day buyers of cars like these already have a dozen contemporary Ferraris, Lamborghinis and Bugattis in the garage.

What cars like the Bentley 4½ Litre offer is a fast-track to the sort of exclusivity that only a unique story can bring. And as Sotheby's event in Florida is likely to prove, the price of entry to that club isn't about to get cheaper any time soon.